YouTube app videos stuck in ambient mode?

Using Pixel 9 Pro XL running Android 15.

I have YouTube video settings to turn off ambient mode so that the black bars are solid black, but I've picked up my phone today and for whatever reason the black bars are grey just like ambient mode. I've tried changing the settings, tried clearing the cache, tried rebooting the phone, still no difference.

Have they changed this? Ambient mode is a complete distraction and ruins the picture. Any tips on how to resolve this?